Residence time distribution of a purely viscous non-Newtonian fluid in helically coiled or spatially chaotic flows

Influence of whey protein aggregation on the residence time distribution in a tubular heat exchanger and a helical holding tube during heat treatment process

“…In fact, for series of tubes connected by bends and helically coiled systems in laminar regime, the parabolic velocity profile is altered by the presence of centrifugal forces exerted by the curvature of the tube. This phenomenon results on secondary flow materialized by two contra-rotative vortices called Dean cells (Dean, 1927) (Palazoglu and Sandeep, 2002;Castelain and Legentilhomme, 2006). The secondary flow is characterized by the Dean number (D n ) defined in Eq.…”

Influence of flow regime and thermal power on residence time distribution in tubular Joule Effect Heaters

“…Their results lead to an efficiency factor (ratio between pressure drop and heat transfer coefficient increases) of about 1.2 for Re < 3000. Castelain et al (1997Castelain et al ( ,2006 and Chagny et al (2000) investigated the efficiency of chaotic advection regime in a twisted duct flow. A configuration representing a three dimensional steady open flow consisted of helical and chaotic mixers made of identical bends.…”

Development of a time temperature integrator for quantification of thermal treatment in scraped surface heat exchangers

“…Most of the RTD studies done up to now are dealing with the influence of different design features or operating conditions on the flow pattern (Lee & Singh, 1993;Chandarana & Unverferth, 1996;Alhamdan & Sastry, 1997, 1998 but, as said before, do not give information on the temperature profile in the exchanger. The most used model to represent residence type distributions with or without reaction in tubular reactors or exchangers is the plug flow model with axial dispersion (Roetzel & Balzereit, 2000;Kudrna, Jahoda, Siyakatshana, Cermakova & Machon, 2004;Castelain & Legentilhomme, 2006), but also in less classical geometries such as Taylor-Poisseuille vortex flow (Giodano, Giordano, Prazares & Cooney, 2000) or torus reactor (Benkhelifa, Legrand, Legentilhomme & Montillet, 2000). RTD measurements in scraped surface heat exchangers have also been handled in our laboratory (Mabit, Loisel, Fayolle & Legrand, 2004;.…”